Outer seal for first stage turbine

ABSTRACT

An outer air seal for the first stage turbine of an engine having the seal segments made of a high strength base material with a highly oxidation-corrosion resistant abradable alloy layer bonded to the surface thereof on the side adjacent the rotor blade. Another embodiment having an abrasive layer bonded to the high strength base material with the abradable layer being bonded to the abrasive layer.

United States Patent 1 Corey et al.

.[ Apr. 29, 1975 1 OUTER SEAL FOR FIRST STAGE TURBINE [75] Inventors:Arthur F. Corey. Glastonbury:

Bruce E. Snyder. South Windsor. both of Conn.

[731 Assignee: The United States of America as represented by theSecretary of the Air Force, Washington. DC.

[22] Filed: Feb. 22, 1974 [21] Appl. No.: 445.047

[52] US. Cl 415/174; 277/96 [51] Int. Cl. F0ld 11/00 [58] Field ofSearch 415/174', 277/96 [56] References Cited UNITED STATES PATENTS2.742224 4/1956 Burhans 415/174 3.092.306 6/1963 Edcr 415/174 3.291.38212/1966 Blackhurst et 415/174 3.537.713 11/1970 Matthews et al. 415/174Primary E.\'uminerRobert 1. Smith ASS/Mil!!! E.\'aminerRobert 1. SmithAllvrney. Agent. or Firm-Harry A. Herbert, Jr.; Richard J. Killoren [57]ABSTRACT An outer air seal for the first stage turbine of an enginehaving the seal segments made of a high strength base material with ahighly oxidation-corrosion resistant abradable alloy layer bonded to thesurface thereof on the side adjacent the rotor blade. Another embodimenthaving an abrasive layer bonded to the high strength base material withthe abradable layer being bonded to the abrasive layer.

4 Claims, 3 Drawing Figures OUTER SEAL FOR FIRST STAGE TURBINE RIGHTS OFTHE GOVERNMENT The invention described herein may be manufactured andused by or for the Government of the United States for all governmentalpurposes without the payment of any royalty.

BACKGROUND OF THE INVENTION The outer air seals for the first stageturbine of the TF30 engine and the JT9D engine use a single material forthe seal segments. The material is selected with a compromise betweenstrength and corrosion resistance. In the past, abradable surfaces onthe seals have prior art structure except the seal 14.

The seal segments 16, one of which is shown in FIG. 2, have a basemember 24 of a material PWA 647 or PWA 663 with highlyoxidation-corrosion resistant abradable layer 26 of PWA 1045 NiCrAlYdiffusion bonded to the base material by heating for 1 hour to between1,300 and 1.400F in a vacuum at a pressure between 145 and 275meganewtons per square meter and then postheating two hours to between1,900 and 2,l50F at a pressure of about 15 meganewtons per square meter.Before bonding the surfaces are cleaned by sanding and then eitherchemical polishing or electropolishing. The material PWA 662, PWA 647and PWA 1045 will be described in greater detail below.

been used but these have been unsuccessful since a A modlficatlon of thedevlce of FIGS. 1 and 2 compound of sufficient abradabihty withoutundesirshown in FIG. 3. In this device. the seal segments 16 able sideeffects, such as corrosion, had not been have a layer 28 of abrasivematerial WS-6 bonded to found. Thus, abradable surfaces were eliminatedand the desi n returned to sin le material se'tl se ments the basemember wlth the abradable layer 26 of PWA g g g 1045 being bonded to theabrasive layer 28. This will BRIEF SUMMARY OF THE INVENTION allowincrusion of the moving rotor blade tip into the A I abradable layeruntil it reaches the abrasive layer Ccor mg to f bed g are T whereuponsome machining of the blade tip by the vlded for the outer seal of thefirst stage turbine abrasive laygr would occur wherein a highlyoxidation-corrosion resistant abradas The Composition f the materialsPWA 1045 PWA able alloy 15 bonded to a strong high temperature alloy,661 PWA 647 d W5 5 are given i h f ll i thus eliminating the propertycompromise necessitated table wherein the parts by weight given are of100 total by the use of a single alloy. In another embodiment, an parts.

PWA 1045 PWA 663 PWA 647 WS 6 Aluminum 55 6.0 Bismuth 0.5 PPM max Boron0.003 max 0.015 0.01 max Carbon 0.05 0.1 1 0.6 0.9 Chromium 16.00 8.023.4 25.0 Cobalt 10.0 Remainder Remainder Columbium 0.10 max 1.0 Iron0.75 max 0.35 max 1.50 max 1 0 Lead 10 PPM max Manganese 0.50 max 0.20max 0.10 max Molybdenum 6.0 Nickel Remainder Remainder 10.0 15.0Phosphorous 0.015 max Silicon 0.40 max 0.25 max 0.40 max Sulfur 0.015max 0.015 max 0.015 max Tantalum 4.25 3.5 2.75 Titanium 1.0 0.2 0.9Tungsten 0.10 max 7.0 7.75 Yttrium 0.2 Zirconium 0.075 0.45 0.4

abrasive material is bonded to the high strength mate- The terms PWA1045, PWA 663, PWA 647 and rial with the highly oxidation-corrosionresistant layer S-6 as us d in th specification and clalms willIndibeing bonded to the abrasive material. Cate the Composition as givenin thls table- In some applications, other alloys than those given INTHE DRAWING may be used for the base member 24. FIG. 1 is a partiallyschematic cut away sectional Them 15 thus provldefi an P Outer Seal ofview of the first stage turbine of an engine with the the first slageOfa turbme engmeouter air seal of the invention. We

1. An outer seal for the first stage of a turbine engine,

FIG. 2 is an elongated sectional view of an outer air seal of the deviceof FIG. 1.

FIG. 3 is an enlarged sectional view of an outer air seal for the deviceof FIG. 1 according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Reference is now made to FIG. 1 ofthe drawing which shows the first stage rotor assembly 10 having rotorblades 12, one of which is shown. positioned adjacent the outer air seal14. The outer air seal 14 has a plurality of segments 16 positionedaround the rotor assembly. The segments 16 are supported on supportelements 18 and 20 on a support member 21 which are supported on theouter case 22. All of this structure is comprising an annular sealsegment support member surrounding the blades of the first stage of theturbine engine; a plurality of seal segments supported on the sealsegment support member; said seal segments having a layer of PWA 1045sheet material bonded to a high strength Nickel-Chrominum alloy basematerial.

2. The device as recited in claim 1 wherein the high strength basematerial is PWA 663.

3. The device as recited in claim 1 wherein the high strength basematerial is PWA 647.

4. The device as recited in claim 1 wherein an abrasive layer of WS-6 isbonded to the high strength base material between the base material andthe sheet of PWA 1045.

1. An outer seal for the first stage of a turbine engine, comprising anannular seal segment support member surrounding the blades of the firststage of the turbine engine; a plurality of seal segments supported onthe seal segment support member; said seal segments having a layer ofPWA 1045 sheet material bonded to a high strength Nickel-Chrominum alloybase material.
 2. The device as recited in claim 1 wherein the highstrength base material is PWA
 663. 3. The device as recited in claim 1wherein the high strength base material is PWA
 647. 4. The device asrecited in claim 1 wherein an abrasive layer of WS-6 is bonded to thehigh strength base material between the base material and the sheet ofPWA 1045.